Often considered the father of geology and stratigraphy, Danish Catholic bishop and scientist Blessed Nicolas Steno was born 11 January in 1638 in Copenhagen. His pioneering research in both anatomy and geology has led to a greater understanding in both, and he was also beatified by Pope John Paul II in 1988. He was the son of a Lutheran goldsmith who worked regularly for King Christian IV of Denmark, but grew up in isolation during his childhood, because of an unknown disease. In 1644 his father died, after which his mother married another goldsmith. Across the street lived Peder Schumacher (who would later offer Steno a post as professor in Copenhagen). After completing his university education, Steno set out to travel through Europe, In the Netherlands, France, Italy and Germany he came into contact with prominent physicians and scientists. These influences led him to use his own powers of observation to make important scientific discoveries. At a time when scientific questions were mostly answered by appeal to ancient authorities, Steno was bold enough to trust his own eyes, even when his observations differed from traditional doctrines.
He studied anatomy focusing again on the Lymphatic system and discovered a previously undescribed structure, the “ductus stenonianus” (the duct of the parotid salivary gland) in sheep, dog and rabbit heads. Steno’s name is associated with this structure. Within a few months Steno moved to Leiden, where he met the students Jan Swammerdam, Frederik Ruysch, Reinier de Graaf, Franciscus de le Boe Sylvius, a famous professor, and Baruch Spinoza. At the time Descartes was publishing on the working of the brain, and Steno did not think his explanation of the origin of tears was correct. Steno studied the heart, and determined that it was an ordinary muscle.
He later travelled to Saumur and Montpellier, where his work was introduced to the Royal Society. In Pisa, Steno met the Grand Duke of Tuscany, who supported arts and science. Steno was invited to live in the Palazzo Vecchio, he also went to Rome and met Alexander VII and Marcello Malpighi. As an anatomist in the hospital Steno focused on the muscular system and the nature of muscle contraction. He also became a member of Accademia del Cimento in Florence. Like Vincenzio Viviani, Steno used geometry to show that a contracting muscle changes its shape but not its volume.
Steno also dissected a sharks head and noted that the shark’s teeth bore a striking resemblance to certain stony objects, found embedded within rock formations. at the time these were known as glossopetrae or “tongue stones” by Ancient authorities, such as the Roman author Pliny the Elder, who had suggested in his book Naturalis Historia that these stones had fallen from the sky or from the Moon, while Others thought, that fossils grew natuarally in the rocks. Fabio Colonna, however, had already shown in a convincing way that glossopetrae were shark teeth and Steno added to the discussion on the differences in composition between glossopetrae and living sharks’ teeth, arguing that the chemical composition of fossils could be altered without changing their form, using the contemporary corpuscular theory of matter.
This led him to the question of how any solid object could come to be found inside another solid object, such as a rock or a layer of rock. The “solid bodies within solids” that attracted Steno’s interest included not only fossils, as we would define them today, but minerals, crystals, encrustations, veins, and even entire rock layers or strata. He published his geologic studies in De solido intra solidum naturaliter contento dissertationis prodromus, or Preliminary discourse to a dissertation on a solid body naturally contained within a solid in 1669. Steno was not the first to identify fossils as being from living organisms; his contemporaries Robert Hooke and John Ray also argued that fossils were the remains of once-living organisms.
Steno, in his Dissertationis prodromus is credited with three of the defining principles of the science of stratigraphy: the law of superposition, the principle of original horizontality and the principle of cross-cutting discontinuities. These principles were applied and extended in 1772 by Jean-Baptiste L. Romé de l’Isle. Steno’s landmark theory that the fossil record was a chronology of different living creatures in different eras was a sine qua non for Darwin’s theory of natural selection. Despite Having been brought up in the Lutheran faith, Steno also questioned its teachings, and After making comparative theological studies, and by using his natural observational skills, he decided that Catholicism, rather than Lutheranism, provided more sustenance for his constant inquisitiveness. Steno converted to Catholicism. In 1675 Steno was ordained a priest. Athanasius Kircher expressly asked why Steno had left science and became one of the leading figures in the Counter-Reformation.
In 1684 Steno moved to Hamburg and became involved in the study of the brain and the nerve system with an old friend Dirck Kerckring. Steno was invited to Schwerin. To test his theory Steno dressed like a poor man in an old cloak and drove in an open carriage in snow and rain. Living four days a week on bread and beer, he became emaciated. When Steno had fulfilled his mission, he wanted to go back to Italy. Sadly though Steno died whilst in Germany on 5th December 1686, His corpse was shipped by Kerckring to Florence and buried in the Basilica of San Lorenzo close to his protectors, the De’ Medici family. In 1953 his grave was discovered, and the corpse was reburied after a procession through the streets of the city.
The Steno Museum in Århus, Denmark, is named after Steno, and holds exhibitions on the history of science and medicine, and also has a planetarium and a medicinal herb garden. Impact craters on Mars and the Moon have also been named in his honour. In 1950 the “Niels Steensens Gymnasium”, a Catholic preparatory school, was founded on a Jesuit monastery in Copenhagen. The Steno Diabetes Center, a research and teaching hospital dedicated to diabetes in Gentofte, Denmark, was also named after Nicolas Steno and The Istituto Niels Stensen, in Florence, is also dedicated to his memory.